Alterations in the photochemical responses of Zea mays L. and Oryza sativa L. were analyzed to compare the tolerance level of these two crops towards Cd and Zn toxicity. To achieve this, photosynthetic efficiency of maize and rice plants was probed on the 8 days of CdCl₂ and ZnSO₄ exposure using chlorophyll a fluorescence kinetics, a noninvasive method suitable to examine the impact of different toxic compounds on photochemistrys. Analysis of induction curves and phenomenological energy pipeline models showed that both Cd and Zn reduced the efficiency of electron transport and associated photosystem II (PSII) functionality. A strong negative correlation was found between the accumulation of reactive oxygen species and ascorbate with the photosynthetic efficiency in both crops, but rice was more tolerant than maize towards Cd and Zn toxicity. Further, we found that Cd strongly affected the early photochemical reactions of maize, which can be considered as the reason for the higher vulnerability of this crop towards Cd. Our study suggests that the non-specific toxic effects of Cd and Zn resulted in chlorophyll degradation, reduction in efficiency of PSII and the disturbance in the electron transport process.

分析了玉米和水稻的光化学反应的变化，以比较这两种作物对镉和锌毒性的耐受水平。为此，使用叶绿素a在CdCl ₂和ZnSO ₄暴露的第8天探测了玉米和水稻植物的光合效率。荧光动力学，一种非侵入性方法，适用于检查不同有毒化合物对光化学的影响。感应曲线和现象学能量管道模型的分析表明，镉和锌都降低了电子传输效率和相关的光系统II（PSII）功能。在两种作物中，活性氧和抗坏血酸的积累与光合作用效率之间存在很强的负相关性，但水稻对玉米的镉和锌毒性耐受性强于玉米。此外，我们发现Cd强烈影响了玉米的早期光化学反应，这可以认为是该作物对Cd较高的脆弱性的原因。我们的研究表明，镉和锌的非特异性毒性作用导致叶绿素降解，